The present invention relates to a household appliance, namely a machine for washing and/or drying laundry, comprising a cabinet, a door and a door block/release device that can be actuated electrically.
Various types of household appliances have the characteristics indicated above. For example, machines for washing and/or drying laundry, be they of the front loading or top loading type, are provided with a door, through which the user has access to a drum, for the normal operations of loading and unloading the laundry. Machines of the aforementioned type are also provided with a device for locking/releasing the door; for regulatory reasons, the aforesaid device incorporates safety means, operative to prevent the door from opening during the operating cycle of the machine, and vice versa the operation of the machine with the door open.
In some types of machines, the locking/releasing device can be operated by means of a handle associated with the door. In the case of front loading laundry washing or drying machines, given the generally lowered position of the door, the actuation of the aforesaid handle forces the user to bend down in tiring fashion.
For this purposes, therefore, machines have been proposed with mechanical transmission systems, to allow to transfer control over the locking/releasing device to a more favourable position, in particular by means of a push-button positioned on the control panel of the machine. Such devices with remote mechanical actuation are oftentimes not fully satisfactory, both due to the high force of control required, and to their structural complexity.
Therefore, locking/releasing mechanisms have also been proposed whose mechanical part is actuated locally by actuator means which are electrically powered as a result of the actuation of a push-button positioned on the control panel of the machine, or as a result of a signal generated by the control system of the household appliance,.
In such electrically actuated devices, in some situation, it is necessary to unlock the door manually. Think for instance of the case of a malfunction of the actuator that actuates the mechanical part of the locking/releasing device, or of a malfunction of the control system that operates said device, or else of an interruption in the mains voltage powering the household appliance.
The document EP-A-0 977 104 discloses a bi-stable actuation system, operated through a wax electro-thermal actuator and usable in combination with a mechanical device for locking/releasing the door of a household appliance. The described system can be unlocked manually, through an appropriate mechanical arrangement, if the need arises, e.g. if main power supply fails or the control system of the household appliance malfunctions. Said arrangement comprises a slot formed in the casing of the device, accessible from the exterior of the household appliance, in which the end of an appropriate tool can be inserted to “reset” the system, towards a respective door release position. The system according to the aforementioned prior document, in addition to requiring the use of an appropriate tool, is complex from the mechanical viewpoint and hence potentially not very reliable over time.